android - How to catch a click event on a button?

Question

.NET Developer here just getting started with Eclipse and Android.

Can someone show me in the simplest way possible, with the absolute fewest lines of code, how to DO something when a button is clicked?

My button has id button1 and I just want to see where/how to write the onClick() handler.

So let's say I have imageview1 set to invisible. How would I make it visible when the button is clicked?

EDIT:

Thanks everyone, but since not a single one of your examples work for me, I'll try this: Can someone please post the ENTIRE code to make this work? Not just the method, because when I try to use ANY of your methods I get errors all over the place so obviously something else is missing. I need to see everything, beginning with all the imports.

Answer 1

/src/com/example/MyClass.java

package com.example

import android.app.Activity;
import android.os.Bundle;
import android.view.View;
import android.view.View.OnClickListener;
import android.widget.Button;
import android.widget.ImageView;

public class MyClass extends Activity
{

  @Override
  public void onCreate(Bundle savedInstanceState)
  {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.main);    

    Button button = (Button) findViewById(R.id.button1);

    button.setOnClickListener(new OnClickListener()
    {
      public void onClick(View v)
      {
         ImageView iv = (ImageView) findViewById(R.id.imageview1);
         iv.setVisibility(View.VISIBLE);
      }
    });

  }
}

/res/layout/main.xml

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout
  xmlns:android="http://schemas.android.com/apk/res/android"
  android:layout_width="fill_parent"
  android:layout_height="fill_parent">
    <Button 
      android:text="Button"
      android:id="@+id/button1"
      android:layout_width="wrap_content" 
      android:layout_height="wrap_content"
    />
    <ImageView 
      android:src="@drawable/image" 
      android:layout_height="wrap_content" 
      android:layout_width="wrap_content" 
      android:id="@+id/imageview1"
      android:visibility="invisible"
    />
</LinearLayout>